Sephiroth could have drawn things out, toyed the spar further... but that was for open conflict when he needed to worry about the aftermath. In a spar? No, in a spar he could go full tilt and deal with his consequences and his eyes glowed with the thrill as he tried to get one last hit in on the other man.

If it didn't force him to concede he would unfortunately have to call for air, and while sad, it was less a loss, more a break to resume anther day.